Markup languages including extensible Markup Language (XML) are known. XML is a set of rules about how to compose markup languages. Any document that conforms to these rules is an XML document. XML is called extensible because it is possible to define other markup languages in XML. XML documents follow a tree structure, which consists of a set of hierarchically arranged nodes. There is a single top level node that contains all other nodes. Each node is marked by tags of the form <node> node body <node>. If a node does not have a body, it may also be written as <node>. Further, a node can have attributes: <node attr1=“first attribute” attr2=“second attribute”/>. Attributes must be enclosed in quotes and preferably do not contain certain characters such as quotes, “<”, “>” and “&”.
The Extensible Stylesheet Language (XSL) is a language used to write stylesheets and that adheres to the XML format. XSL can be applied to any kind of XML-based S markup, even to XSL itself XSL can be used, for example, to transform XML documents into other XML documents or into plain text. An XSL document and processor, provide a mechanism for navigating through the nodes of an XML document and applying certain transformations to them. XSL also allows the use of scripts. Scripts are programs that can provide additional functionality that may not be possible with the standard XSL elements.
Generally, markup languages enable systems to present text based information on a visual display. Markup languages typically, however, do not enable information to be communicated to a voice enabled device.